Table 1.
Characteristics of smokers and non-smokers.
| Smokers (N = 322) | Nonsmokers (N = 306) | F | P | ||
|---|---|---|---|---|---|
| Age (years) | 46.6 ± 11.8 | 45.8 ± 13.3 | 0.46 | >0.05 | |
| Education (years) | 9.1 ± 3.5 | 9.2 ± 3.6 | 0.21 | >0.05 | |
| BMI (Kg/m2) | 25.4 ± 6.1 | 24.9 ± 5.8 | 0.89 | >0.05 | |
| BDNF (ng/ml)a | 11.6 ± 2.3 | 11.5 ± 3.0 | 0.23 | >0.05 | |
| Allele frequency (%) | |||||
| Val | 339 (52.6%) | 304 (49.7%) | 1.11 | >0.05 | |
| Met | 305 (47.4%) | 308 (50.3%) | |||
| Genotype frequency (%) | 2.26 | >0.05 | |||
| Val/Val | 81 (25.1%) | 74 (24.2%) | |||
| Met/Val | 177 (55.0%) | 156 (51.0%) | |||
| Met/Met | 64 (19.9%) | 76 (24.8%) | |||
Note: BMI = body mass index; BDNF = brain-derived neurotrophic factor.
aBDNF serum level data were available from 103 smokers and 89 nonsmokers.